The invention relates to an electronic component and a process for its production.
In many electronic components, a first semiconductor chip module, for example a logic module, and a second semiconductor module, for example a memory module, are needed. In order to save space on a printed circuit board, it is expedient to accommodate both semiconductor chip modules in a common housing with the smallest possible space requirement. Now, a logic module typically has a square base area and a memory module has a rectangular base area, so that when semiconductor chip modules are disposed one above another, as in the case of a known chip-on-chip construction, the bonding contact areas to some extent cover one another. Hitherto, the problem has been solved by the two semiconductor chip modules having been disposed beside each other in a common housing, which gave rise to a considerable space requirement. In an alternative solution, the two semiconductor chip modules were mounted in a lead-frame housing, which entails cumbersome and difficult mounting, since the components have to be turned many times and, in the process, the bonding wires to some extent are exposed. A further principle has also been used, in which the semiconductor chip modules are mounted in different housings that are then disposed above another. However, this is also a complicated and costly process that, in addition, leads to larger and higher installation heights of the electronic component of this type.
Published, Japanese Patent Application JP 08250651-A discloses a semiconductor configuration in which two semiconductor chip modules are disposed one above the other in spaces separated by an intermediate wall. The two semiconductor chip modules are connected to outer contacts via conductor tracks by bonding wires. The known semiconductor configuration takes up a great deal of space and is cumbersome and complicated to produce.
It is accordingly an object of the invention to provide a electronic component and a process for producing the electronic component which overcomes the above-mentioned disadvantages of the prior art devices and methods of this general type, which is constructed simply and can be produced economically and which takes up little space.
With the foregoing and other objects in view there is provided, in accordance with the invention, an electronic component. The electronic component contains a substrate having substrate contact areas and semiconductor chip modules including a first semiconductor chip module and a second semiconductor chip module supported by the substrate. The semiconductor chip modules each have an active chip surface and contact areas disposed on the active chip surface. The active chip surface of the first and second semiconductor chip modules each have a central contact area disposed facing each other. The central contact area of the first and second chip modules have solder contact areas corresponding with one another and disposed opposite and aligned with one another and electrically conductively connected to each other. Bonding wires connect the contact areas of the active chip surface of each of the semiconductor chip modules to the substrate contact areas.
According to the invention, the electronic component has at least the first semiconductor chip module, the second semiconductor chip module, and the substrate to accommodate the semiconductor chip modules.
Bonding wires are provided, which are connected to the contact areas of the active chip surfaces of each semiconductor chip module and the contact connecting areas of the substrate. In this case, the active chip surfaces of the first and second semiconductor chip module each have a central contact area. The central contact areas are disposed to face each other, and individual solder contact areas formed on the central contact areas of the two semiconductor chip modules correspond with one another and are aligned with one another and are electrically conductively connected.
The electronic component according to the invention has the advantage that, as a result of the mutually facing central contact areas of the two semiconductor chip modules with their solder contact areas disposed to correspond to one another, semiconductor chip modules with different external dimensions can be accommodated in an extremely space-saving manner in a common housing. It is therefore possible to stack a rectangular semiconductor chip with a square semiconductor chip and vice-versa, the semiconductor chips overlapping only partly and both semiconductor chips in each case having regions that project beyond the overlap. For different external dimensions of this type, the prior art does not provide any usable solution. In addition, in one embodiment of the invention, the outer contact areas of the two semiconductor chip modules are electrically conductively connected to the corresponding solder contact areas by conductor tracks, by which thermal stresses during the mounting of the electronic component according to the invention on a printed circuit board or on a common substrate are reduced.
In an embodiment of the invention, the solder contact areas formed on the central contact areas of the first and second semiconductor chip modules that correspond with one another are disposed in a mirror-image fashion in relation to one another.
The embodiment has the advantage that, by the simple procedure of laying one semiconductor chip module on the other, it is possible to make contact quickly and reliably between the first and second semiconductor modules.
A further embodiment provides for contact bumps to be provided between the opposite solder contact areas of the mutually facing central contact areas of the first and second semiconductor chip modules. In the embodiment, it is advantageous that making contact between one semiconductor chip module and the other semiconductor chip module can be carried out effectively and economically by a single heating operation. In this case, the contact bumps can be connected electrically to the solder contact areas of the first and second semiconductor chip modules, for example by eutectic soldering.
In a further embodiment of the invention, provision is made for one contact bump to be formed as a pillar bump and for its height to be greater than the radius of its base area. On the basis of the configuration of the contact bumps, accurate and efficient making of contact between the first and the second semiconductor chip modules is possible, the electrical connection of the two semiconductor chip modules being carried out by a flip-chip technique.
The advantage of an electronic component constructed and produced in accordance with the invention is that a logic module having a rectangular form and a memory module having a square form can be reliably connected electrically to one another in a small space. A significant advantage arises from the fact that the bonding wires for electrical connection are provided only between the second semiconductor chip module and the substrate.
A process for the production of an electronic component contains is now described. A first semiconductor chip module with a central contact area is provided. A second semiconductor chip module with a central contact area and a substrate with a chip island and outer contact areas are provided. The second semiconductor chip module is fixed on the chip island of the substrate by a conductive adhesive layer or solder layer. Bonding wires are connected between the contact areas of the second semiconductor chip module and the outer contact areas of the substrate. The first semiconductor is fitted with contact bumps. The first semiconductor chip module is applied to the second semiconductor chip module seated on the substrate by a flip-chip technique. The electronic component (i.e. the semiconductor chip modules and the substrate) is potted in a housing.
The process for the production of an electronic component has the advantage that it has very short production times since the use of the flip-chip technique results in that making electrical contact between the first and the second semiconductor chip module can be carried out in a time-saving manner by the respective central contact areas disposed in mirror-image fashion on the two opposite semiconductor chip modules.
In addition, the product of the process, the electronic component, has a very compact configuration.
In an exemplary implementation of the process, sets of the first semiconductor chip module and the second semiconductor chip module are disposed on the chip island of the upper side of the substrate and on the opposite chip island of the underside of the substrate.
The advantage of the exemplary implementation is a further increase in the performance of such electronic components, with a considerably reduced requirement for space.
The invention permits the implementation of very compact electronic components, in that all the electrical connections of the two semiconductor chip modules are in each case disposed as solder contact points in a central contact area in such a way that they are initially located in mirror-image fashion in relation to one another and, when the first semiconductor chip module is placed inverted on the second semiconductor chip module by the flip-chip technique, the mutually associated contact points are aligned with one another. Electrical contact is made by contact bumps, which are formed as pillar bumps and, as high melting-point solder connections, connect the contact areas of the semiconductor chips lying one above another electrically to one another. In addition, it is ensured that the bonding wires running between the substrate and the semiconductor chip module connected thereto are not touched by the semiconductor chip module located above.
The advantages of the invention reside in the fact that no rewiring on the substrate is required, and in that optimum performance between the first and second semiconductor chip modules is achieved as a result of the short signal paths. In spite of the unfavorable geometric dimensions of the two semiconductor chip modules, an electronic component that has a small structure and can be produced economically is provided by the combination of the wire-bonding technique with the flip-chip technique, using pillar bumps as spacers.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a electronic component and a process for producing the electronic component, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.